Bilateral Double-Layered Patella (DLP) with Suprapatellar Impingement

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Bilateral Double-Layered Patella (DLP) with Suprapatellar Impingement

João Araújo^*
Department of Radiology, Centro Hospitalar do Porto, Portugal

^*Corresponding author: João Araújo, Department of Radiology, Centro Hospitalar do Porto, Portugal

Published: 10 Jan, 2017
Cite this article as: Araújo J. Bilateral Double-Layered Patella (DLP) with Suprapatellar Impingement. Ann Clin Case Rep. 2017; 2: 1231.

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A 22 year-old man presented complaining of anterior knee pain and no history of trauma. A Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) were performed, demonstrating two patellar layers bilateral, one anterior and one posterior on both knees, confirming the diagnosis of bilateral DLP. We found the anterior osseous patellar layer attached to the extensor mechanism. In the MRI, both knees had fluid like signal replacing the normal supra patellar fat pad, which we assumed to be the cause of the paindue to the impingement with the femoral trochlea. No significant chondropathy was founded.
The DLP is a rare entity [1] that consists of two distinct patellar layers, one anterior and one posterior. The literature admits frequent association of DLP with autosomal recessive form of multiple epiphyseal dysplasia (MED) [2,3]. An all body X-ray was performed and there were no signs that suggest that association.

Figure 1

Figure 1
Axial bone window CT of the knees demonstrating two patellar layers and normal patella femoral joint space.

Figure 2

Figure 2
Sagittal proton density fast spin echo MRI (A) and sagittal proton density with fat suppression fast spin echo MRI of the left knee demonstrating cartilage tissue between the two layers (yellow arrow). The anterior osseous patellar layer is attached to the extensor mechanism. There´s also fluid like signal replacing the normal suprapatellarfat pad (blue arrow).

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